Backset extension unit for door locks



y 1 Ocf- 20, 1942 w. R. scHLAGE 2,299,181

BACKSET EXTENSION UNIT FOR DOOR LOCKS Filed Aug. 24, 1940 2 sheets-sheet 1 El lili/Eli?.

HMM.

ATTORNEY oct. 2o, 1942,

w. R. scHLAGE BACKSET EXTENSION UNIT FOR DOOR LOCKS Filed Aug. 24, 1940 2 Sheets-Sheet ATTORNEY Patented Oct. 20, 1942 BACKSET EXTENSION UNIT FOR DOOR LOCKS Walter R. Schlage, Burlingame, Calif., assignor to Schlage Lock Company, San Francisco, Calif., a corporation of California Application August 24, 1940, Serial 2 claims. (c1. 29g- 337) This invention relates to an extension unit whereby the backset of a lock unit when installed in a door may be materially increased, the present application being a continuation in part of my co-pending application Serial Number 277,768, filed June 7, 1939, now Patent No. 2,250,036, dated July 22, 1941, entitled Backset extension unit for door locks.

Backset is a term used in the door lock and building industry, and refers to the measurement or distance between the edge of the door and the center of the lock spindle. The average backset on inside doors is 21/2 inches', and the backset on outside or so-called front doors, 2% inches. Architects and builders are constantly attempting to make innovations, that is, to introduce new features, novelties, new designs, etc., and recently it has become the vogue in certain types of buildings and other structures materially to increase the backset in door locks. In some instances this is carried to such an eX- treme as to position the spindle and`knobs approximately at the center of a door.

In certain types of lock, for instance in the so-called mortise type, the latch bolt and the latch bolt actuating mechanism, to wit, the spindle, the rollback member, the knobs, etc., are carried by a single housing. To increase the backset in that type of lock it would be necessary to increase the length of the housing and of much of the mechanism within the housingobviously, a very costly procedure. There is another type of door lock which is divided into two separate units, each enclosed in its own housing. These units are known as the latch bolt unit and the latch bolt actuating unit. In this type of lock, increase of the backset has been accomplished. by lengthening the housing and :contained mechanism of the latch bolt unit. This is also costly and is not very satisfactory, and it compels the lock manufacturer to furnish the latch bolt unit in varying lengths depending upon the backset desired.

Whether the housing and mechanism of the mortise type of lock is lengthened, or the latch bolt unit of the latter type of lock is lengthened, the cost to the lock manufacturer is excessive; and besides that, a considerable stock of locks of varying lengths must be carried to meet the speciiic measurements and lengths demanded by different architects and builders.

The object of the present invention is to improve locks of the two-unit type, that is, in which the lock mechanism consists of two separable units, 'v to wit, a latch bolt unit and a latch bolt actuating unit; and particularly, to provide an intermediate or extension unit, insertable between the latch bolt unit and the latch bolt actuating unit, whereby any backset may be obtained without change or increase of the length of either of the rst named units.

The invention is shown by way of illustration in the accompanying drawings, in which Fig. 1 is a central longitudinal vertical section, taken through the type of lock heretofore' Fig. 3 is a longitudinal horizontal section, taken at right angles to Fig. 1 or Fig. 2, of the extension or intermediate unit;

Fig. 4 is a perspective View of the retractor bar carried by the extension or intermediate unit;

Fig. 5 is a perspective view of the latch bolt actuating unit;

Fig. 6 is a perspective View of the extension or Y intermediate unit;

Fig. 7 is a perspective View of the latch bolt unit;and

Fig. 8 is a fragmentary perspective View of a door, showing the manner in which it is bored and otherwise prepared for the reception of the type of lock shown in Figs. 5, 6 and 7. l

The type of door lock mechanism to which the present invention appears most readily applicable is the separable type, that is, a lock in which the latch bolt mechanism is contained in one housing or unit and the latch bolt actuating mechanism in another housing or unit, the two housings with their enclosed mechanism being separably insertable in a door when installing the lock. In order that the extension unit forming the subject matter of this application may be fully understood, a brief :description of the latch bolt unit and the latch bolt actuating unit will be submitted.

The latch bolt unit (see Figs. 1 and 7) coma face plate 2 which is adapted to be secured to the outer edge 3 of a door A by means of screws 6. The face plate has an opening formed therein through which the latch bolt 'I extends in the usual manner. Secured to the rear side of the face plate is a cylindrical elongated housing 8; the rear or inner end of this housing is closed by an end plate 9, but this plate has an opening formed therein, which forms a guide and permits the inner end of a retractor bar I to extend therethrough. The forward end of the .bar is secured to the latch bolt '1; hence when a pull is exerted on the retractor bar the latch bolt will be retracted. Conversely, when a pull is not exerted, a spring II interposed between the latch bolt and the end plate 9 will maintain the latch bolt in extended. position.

The latch bolt actuating unit is generally indicatedat B (see Figs. 1A and 5). a housing I4, which is materially larger in diameter than the latch bolt housing. Extending through the housing and journaled therein is a` spindle I5, and formed on thespindle is aroll.- back member I6, which imparts reciprocal movement to a retractor I1 when the spindle is'rotated. The retractor is provided at its forward end with a pair of spaced fingers I8 whichV under normal conditions engage a pair of lugs' I9:

formed on the inner end of the retractor bar IIJ. This normalv condition will existv as longVK as the standard backset, for instance 21/2l inches, is employed, but where the backsetisincreased, engagement betweenfthe ingers I8 andfthelugs I9 can obviously not be maintained', unless the latch bolt, retractor bar II), and housing 8 are proportionately lengthened. This ofcourse is not feasible from amanufacturing point of' view, and-is the main reason for providing an extension or intermediate unit, generally indicatedat C, which may be interposed between the latch bolt unit and the latch bolt actuating unit.

The extension or intermediate unit is best illustrated in Figs. 1, 2, 3, 4 and 6. It comprises an elongated cylindrically-shaped housing 20L having the same diameter as the latch bolt housing 8. One end of the housing 20 is'open, as indicated at 2|-, and is providedy with a pair of inturned lugs 22, while the other end is provided with a pair of outwardly-turned lugs 23. The end of the housing adjacent lugs 23 is closed by a disc 24-and` a pairofin-turned lugs'25. Slidably mounted within the housing 20 isa retractor bar 26. One end of the bar extends through the disc 24 and'is guided thereby, while the opposite end is provided with a head, generally indicated at E, which serves asV a' guide and also as a connector. The head consists'of a pair of plates 21 connectedV by a side plate 28. The plates 21 are riveted, welded, or'otherwise secured to the bar 26 as shown at 29, and the forward ends of the plates are bent inwardly and shouldered, as shown at 30, to form a pair of fingers which are adapted to receive and embrace the lugs I9 formed on the inner end of the retractor bar IIJ of the latch bolt unit. The opposite end of bar 26 is provided with a pair Vof lugs I9a, and these are adapted to be received and embraced by the ngers I8 of the retractor I1 carried by the latch bolt actuatingunit. A spring 32 surrounds the bar 26; it is interposed between thedisc 24 and ashoulder 26a on the bar 26, and asa compression type of spring is employed, theV tendencyy is tomoveA theV bar in the direction of the arrow (see Fig. 3-). Such movement is, however, limitedV by a stoplug 33 formed on the sideof the bar, as this lug engages the disc 24- and thereby limitsmovement in the direction of the arrow; on the other hand it permits movement inthe opposite direction, as will hereinafter appear.

In actual practice, when a lock;y ofv this character is to be installed in a door, two holes must be drilled with a wood'bit orsimilar tool. One

It compriseshole (see Fig. 8)- isl bored transversely-through 75 the door, as indicated at 40, and receives the latch bolt actuating unit indicated at B. The other hole 4I is drilled through the edge of the door in a direction at right angles to the rst hole, and this hole serves the function of receiving the intermediate unit C and the latch bolt unit shown in Fig. 7. The distance between the edge of the door and the center of the hole 40 depends upon the backset desired, and may in extreme instances be great enough to place the hole substantially in the center of the door. In this particular instance let it be assumed that a backet of six inches is desired. If that is the case, the extension or intermediate unit will have tobeA approximately 31/2 inches long, as the normal-backset is 21/ inches. If the backset on another door is to be eight inches, the extension unitl will have to:v be 51/2 inches long. These dimensions'are merely submitted to bring out the fact that the length of the extension unit varies; that is, the; manufacturer, instead of changing the standard dimensionsv of the latch. boltunits, merely supplies extension units ofY varying lengths, andl willunder normal conditions havea sufficient number ofA different lengthsonhand to take care of current demand..

When a door has been bored: and the face countersunk for the reception of the face plate 2 of the latch bolt actuating'unit, as .clearlyfshown in Fig. 8, the installation of: the: lock will'bev accomplished as follows: The-latchbolt unit 'I and thel intermediate.t or extension unit: shown inFig. 6 are first connected end to end, thatV is, the adjoining ends showni inFigs; 6 and 7.- areconnected. This is.- accomplished by placing the lugs I9 aty the side ofV the open end. 2.I- of:v the housing 20, then by movin'gthe latch.I bolt unit laterally with relation to, the'intermediate unit, or vice versa, the lugs will'pass behind and. under the fingers: 30 formed onI the forward end of the retractor bar 26. At? the same time. the in-turned lugs 22 on the.y housing 20Aof'the1intermediate unitwilly pass behindI outwardlyturned. lugs 22a. formed on the inner end; of the latch bolt unit, the interlock between: ther several lugs and fingers beingclearly shown. in Fig.v 1. By this method of interlock the-retractor bars I0 and 26 are connected, andlso are the two housings of the respective units. Withv the twor unitsV thus connected,it isonly necessary to insert them endwise through the openinghnformed in the door, and then to securefthe lface plate by inserting. the screws 6. When soinsertedthe lugs I'Sa formed at the inner end'of'the retractor bar 2B.-will.pro ject a slight distance into. the openinglliformed in the door, and so will the out-turnedy lugs 23. Hence when the latch` bolt actuatingunit is inserted endwise throughL the opening: IIII', or. ina direction transverse of the door, 4the fingers: I8. of the main retractor will pass overthe lugs I9a of the retractor barV 26 andengageitlie: same.. An interlock between the inner end of thehousing 20 of the unit C and the housing. ltofith'unit B will also be made, as an'opening: 41 isV formed in the housing I4. Thisopening serves two: functions: rst, it! permits the inner endiofztheiretractor bar 26--or in other words, theV lugs-19a'- to extend into the. housing'. I4', where they. can-be grppedror engaged. by the nngers lsecondly, the opening formsVv two opposed1shoulders-II8, which engage the outwardly-turned lugs 23 formedon the -inner end-of the housing20'of' the intermediate v unit.V Thus an interlock is,` formed between-thehousings' I4' and 2U atone end, and betweeny the'housings 2D' and" 8 atl the opposite end. Also, an interlock is formed between the iingers I8 of the main retractor and the inner end of the retractor bar 26, and an interlock is likewise formed between the fingers 30 at the opposite end of the retractor bar 26 and the lugs I9 formed at the inner end of the main retractor bar I of the latch bolt unit. Hence, when the spindle is rotated, the rollback member I6 will engage the inner face of the retractor I1, forcingr this to move inwardly between guides I1a formed within the housing I4, and against the tension of a spring I1b. During such inward movement of the retractor I1, fingers I8 engage the lugs I9a of the retractor bar 26. The fingers 30 at the opposite end of the retractor bar engage the lugs I9 of the retractor bar I0, and both bars will thus move in unison in an inward direction with the retractor I1, and thu-s cause retraction of the latch bolt 1. On the other hand, when the spindle is released, spring |111 will force the retractor I1 in a forward or outward direction. The springs 32 and I I will at the same time force the retractor bars 26 and I0 in an outward direction, and the latch bolt 1 Will accordingly be projected. In otherl words, a backset of any distance may be obtained, without in any way altering the construction and operation of the two standard units employed, to wit, the latch bolt actuating unit and the latch bolt unit, as intermediate units of any desired length may be furnished whereby a connection is made between the retractor I1 and the retractor bar I0.

In Fig. 1, the extension unit is illustrated in connection with an ordinary door latch. The extension is, however, equally applicable to socalled deadlocking door bolts or latches, as illustrated in Fig. 2. In this type of latch, there s a iioating cam plate 50, which is retracted in unison with the main retractor bar, indicated at I, when the main latch bolt 1a is retracted by means of the retractor bar 26 and the main retractor I1. This oating cam plate must remain stationary and in the position shown in Fig. 2 when the latch bolt 1a and the deadlocking bolt 1b are depressed, as for instance when a door is slammed or closed, as it is only in this position that the deadlocking of the latch bolt 1a can be effected. If the latch bolt 1a should be depressed while the d-oor is closed, by means of a jimmy or like tool, it would be possible for the cam plate to move with it, due to friction between the cam plate and the retractor bar 5I; and if this happened, the deadlocking mechanism would fail, and the door would be opened. Such movement of the cam plate is, however, prevented in the present instance, as spring 32 holds the retractor bar 26 in the full-line position shown in Fig. 2.

In this position, fingers 3B engage shoulders 56 on the cam plate, and thus secure it against movement when the latch-bolt 1a is depressed either by closing of the door or when an attempt is made to depress it by a jimmy or similar tool. The use of the spring 32 is accordingly important, as it prevents floating of the cam plate except at the times when it should float. If it were not for this factor, the spring 32 could be entirely eliminated, as the tension of the latch bolt projecting spring, for instance the one shown at Il in Fig. 1, is more than sufficient to actuate not only the main latch bolt 1 or 1a, but also to restore the retractor bar 26 to normal position after actuation.

While certain features of my invention have been more or less specifically described and illustrated, I wish it understood that; changes may be resorted to within the scope of the appended claims, and that the materials and finish of the parts employed may be according to the wishes of the manufacturer or to varying conditions of use.

Having thus described and illustrated my invention, what I claim and desire to secure by Letters Patent is:

l. An extension unit of the character described, comprising a tubular housing adapted to be interposed between the latch bolt retracting mechanism and the latch bolt of a lock, a bar slidably mounted therein, an end closure at one end of the housing through which one end of the bar extends and in which it is guided, a pair of lugs on the same end of the bar adapted to be connected with the retracting mechanism, a, head member on the opposite end of the bar and forming a guide therefor, and a pair of lingers on the head member adapted to be connected with the latch bolt.

2. An extension unit of the character described, comprising a tubular housing adapted to be interposed between the latch bolt retracting mechanism and the latch bolt of a lock, a bar slidably mounted therein, an end closure at one end of the housing through which one end of the bar extends and in which it is guided, a pair of lugs on the same end of the bar adapted to be connected with the retracting mechanism, a head member on the opposite end of the bar and forming a. guide therefor, a pair of lingers on the head member adapted to be connected with the latch bolt, a spring interposed between the head member and the closed end of the housing to urge the bar in one direction, and a stop lug to limit said movement.

WALTER R. SCHLAGE. 

